Method of making metal wheel rims



Aug. 21- 1928. v 1,681,177

E. E. EINFELDT METHOD OF MAKING METAL WHEEL RIMS Original Filed Feb. 29, 1924 INVENTOR Patented Aug. C21, 1928.

om'reo 1 STATE ERNEST n. ni vrnrnr, cinnamon, was, Assieiton, By nn'snii assass nate;

TO FRENCH a HECHT, INC., on DAVENPORT, IOWA, A conroiitirron on Iowa.

misrrnon OF MAKING METAL WHEEL Ems original application .nie'a February 29, 1924, Serial No. 696,013. Divided and this application filed September 29, 1924 Serial 1105740334.

Thisinvention relates to the productionof metal wheels andhas reference more particu larly to the formation of a Wheel rim in order to produce traction lugs thereon to give the wheel tractive qualities.

The object of the invention. is to form on the rim of the wheelbyaben ding or deforming operation on the metal, traction lugs of maximum height with a minimum bend or displacement of the metah'and to this end; the

invention consists of the improved method in which the marginal edges of a blank are bent at intervals alternately in opposite directlons to give saidedges a wavy outline and thereby produce traction lugstherebn In the accompanyingdrawings IFim- 1 is a crossseet-ion'a'l view, of a blank suitable'for carrying my invention into'eifect in producing a: wheel rim of one form. r

(Fig; 2 a side elevation of the same after the marginal edgesare bentin accordance with my invention to produce .traction lugs,

the said figure; showing the bent j rim connected withythe spokes of a'wheel.

Fig. 3}isa cross sectionof the same.

Fig. 4iisia plan view of the bent rim.

. Fig. 5 is a cross sectional view of ablank suitable for the practice of my invention in producing a wheelfim of a different form.

F 6is a sideelevation of the same after the marginal edges of the blank are bent, the

said figure showingthe bent rim connected.

with the spokes of afwheel.

Fig. 7 is a cross section through the same. Referring to thedra-wings V In carrying my invention intoefi'eot in producing a wheel rim of the form shown 1n Figs. 2 to t, a sheet metal blank A is provided as shown in Fig. 1,which is formedwith a central circumferential groove 1, and which is given the arcuate form in cross section as shown. The marginal edges of the blank are i now by suitable means or devices bent alternately in opposite directions from a common base line represented by the edges 2, said edges being bent each upwardly at intervals as indicated by the dotted. line 3 at the right of the figure, and being bent downwardly at intervals as indicated by the dotted line 4 at the left of the figure,;thereby producing the oppositely facing depressions or cavities 5 and 6 and the traction lugs as shown in Figs. 2 and 3. The metal is so manipulated in the bending op ion ha h PrQsSiQn and.

tread portion. p

The effect of the formation of the marginal projections will be disposed transversely of the rim, will be 'ofthe greatest depth at the marginal edges thereof, and will gradually decrease in depth towards the center of the i rim where they will vanish in the central edges of the rim as described, is to give said edges-a wavy outline and produce corrugations which join each other and whichextend continuously around the entire circumference of the rim. This formation producesa constructiou of great strength and stiffness and V as described, a portion of the effective height of thetraction lugs is givenby the bendingof a section of the metal in one direction, and the remaining portion is given by the bending of anadjacent-section of the metal in the opposite direction, so that a given section of the.

metal is displaced for substantially half of the height ofthe lug produced. i This method of procedure produces a rim'which is of great stiffness and strength tliroughout its transl verse and circumferential extent, andv is free:

from the'weakness which would'be created by an undue stretch or bending of the metal.

lVith reference to Figs. 3 and 4 it will be seen thatvthe two series of depressions and corresponding projections forming the traction lugs at the opposite edges of the rim, terminate at theirinner adjacent ends in the side walls of the groove 1, slightly intersecting the sameand thereby producing slight projections 8 on said walls at. intervals around the rim. These walls of the groove constitute the central tread portion of the rim, which tread portion travels on hard roads or ground with no roughness of travel except as produced by the slight pro jections 8, but on softer roads or soil, the tread portion sinks and the traction lugs are brought into action.

The result of the practice of the method as described in connection with a blank of the form shown in Fig. 1 is the product-ion of a wheel rim arcuate in cross section and crowned or convexed on its outer side.

In Figs. 6 and 7 a rim is shown produced by my improved. method, which while also p 4 1,681,117- PATENT err-ace.

arcuate in cross section, of the opposite transverse curvature, or in other words is concave on its outer side. To produce a rim of this form, a blank ll of the form shown in Fig. 5 is provided which is curved inwardly between its circim'it'erential edges so as to present a transverse concavity at its outer face, and the marginal edges of the blank are bent alternately outwardly and inwardly, as in the first case described, from a base line represented by the edges 1) of the blank, respectively to the dotted line positions 10, thereby producing the oppositely facing depressions 1i and 12 and the traction lugs 13 as shown in Figs. (3 and 7. and s milarly in this case, the cfl'ect of the practice oi the method is to form the marginal edges ot the blank wavy in outline and produce c iirrugations in the rim joining each other and extemling continuousl around the entire circumference.

\Yhile in the foregoing description and accompanying drawings l haveset i'orth my improved method of procedure as embodying the :pecitic steps described suitable for the ends in view, it will be understood that. these steps of procedure may he changed and modified without departing from the spirit of the invention; and it. will be understood that the invention is not limited to the exact m"thod of procedure set forth except in so far as such lin'iitations are spccilied in the claims.

Having thus described my invention, what I claim isi 1. The method of shaping a sheet metal blank to form a wheel rim with traction lugs, which consists in bending the marginal edge of the blank atintervals alternatelv in opposite directions from a common base line coincident with said marginal edge before bending, to produce traction lugs thereon having an eflective height subst'antially greater than the extent of bend of the metal in one direction.

2. The method ofshaping a sheet metal blank to form a wheel rim with traction lugs, which consists in first giving said blank an arcuate form in cross section, and then bending the marginal edge of the arcuate blank. at intervals alternately in opposite directions from a common base line coincident with the edge of the arcuate blank before bending, to produce traction lugs thereon having an etl'ective height substantially ,o'rezztcr than the extent of bend oi the metal in one direction.

The method of shaping a sheet metal blank to "form a wheel rim with traction lugs, which consists in forming in the blank a longitudinal groove and giving said blank an arcuate form in cross section, then bending the marginal edge of the blank at intervals alternately in opposite directions from a common base line coincident with the edge of the blank before bending to produce transversely extending depressions and corresponding projections constituting traction lugs having an effective height substantially greater than the extent of the bend of the metal in one direction, and so manipulating the metal in the bending operation that the depressions and projections will be of the greatest depth at the marginal edge of the blank and will decrease in depth toward the groove and will vanish in said groove.

In testimony whereof, I have aliixed my signature hereto.

ERNEST E. EINFELDT. 

